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If the power supply starting ( and suppling the spike) is the problem, why not just use either a timed relay or some type of opto to hook the driver circuit to the power circuit after the power supply has become stable?

Maybe yes, maybe no?

I know *just* enough about circuit design to get me into alot of real world trouble.

softstart is very useful on both diodes and scanners, most modern systems have it on both turn up and turndown, and there are cheap, power fail sensing chips, usually in 3 pin transistor package.

For hobby use, a simple relay across the diode, with some damping diodes across the relay coil and on the relay power will suffice. Mr Murphy comes to get you at showtime, not on the bench. I'll dig up the slow start schematics for the omni 150 argon and the 60X.

the 150 counts to 30 seconds using a 4040 cmos counter driving a mostfet, which costs about 75 cents, and the 60X uses a 555 timer and a relay.

A P channel mosfet defaults to on, so you just make its gate positive with it across teh diode to lite the diode.

It is especially wise to have your scanners wait till both supplies are at rails, older opamps can latch up when the negative rail comes up before the plus one.

Everyone might want to take a look at this. This is, essentially, a soft-start directly for the laser diode itself. It guarantees that, whatever happens in the power supply or the rest of the electrical circuits, spikes won't be able to get to the laser diode.

The LASORB IP has been available since late 2008 and is already incorporated into drivers of an aerospace company and also a really famous laser diode and fiber optic company for whom we would all know their names (but I don't know if we have permission to reveal that they use an outside vendor, so I won't mention their name). As the video says, LASORB is a collection of components, so these components can be placed onto a laser diode driver and work that way.

We are in the final processes of producing encapsulated parts right now, and these should be available within a month. We just have some more testing to do of the encapsulated parts. (Pangolin is a company that tests and tests and tests things before their release.)

The price is somewhere between $2 and $8, depending on the quantity, so it is quite reasonable. Certainly VERY cheap insurance for any laser diode!

Everyone might want to take a look at this. This is, essentially, a soft-start directly for the laser diode itself. It guarantees that, whatever happens in the power supply or the rest of the electrical circuits, spikes won't be able to get to the laser diode.

WOW! Very cool Bill! I definitely want to buy a couple. I always pictured "LASORB" as a fairly large and complicated circuit. That's obviously not the case. Are their any voltage or current constraints? For instance, could you run a 30W diode bar?
Thanks!
Adam

WOW! Very cool Bill! I definitely want to buy a couple. I always pictured "LASORB" as a fairly large and complicated circuit. That's obviously not the case. Are their any voltage or current constraints? For instance, could you run a 30W diode bar?
Thanks!
Adam

Hi Adam,

We have tried it on a number of laser diodes, including diode bars. Yes, it works on those too. It's a pretty neat little circuit. I was amazed that nobody thought of it before (as evidenced by nothing like it in the Patent database or commercially-available systems).